1	import Base
2	import ./change_tick.bend as Tick
3	import ./event_runtime.bend as Ev
4	import ./relation_commands.bend as A
5	import ./relation_types.bend as G
6	import ./relation_graph.bend as Graph
7	import ./capabilities.bend as Cap
8	import ./inspector_stream_frame.bend as F
9	
10	# Selects a relation failure projection by descriptor key. The descriptor must
11	# belong to the application schema; this raw declaration does not validate it.
12	type Declaration<S:Data> is Data:
13	  Declaration{relation:G.Descriptor<S>}
14	# This declaration-scoped grant exposes selected failures and non-payload
15	# timing only. Shared Notice payloads and reader counts stay in the owner harness.
16	type FailureView<S:Data,E:Data> is Data:
17	  FailureView{relation:G.Descriptor<S>,visible:List<&2,G.Failure<S>>,retained:List<&2,G.Failure<S>>,tick:Nat,boundary:Nat}
18	def selected(~S:Data,keep:Bool,failure:G.Failure<S>,rest:List<&2,G.Failure<S>>) -> List<&2,G.Failure<S>>:
19	  match keep:
20	    case False{}:rest
21	    case True{}:failure <> rest
22	def select_failure(~S:Data,+relation:G.Descriptor<S>,+failure:G.Failure<S>,rest:List<&2,G.Failure<S>>) -> List<&2,G.Failure<S>>:
23	  match failure:
24	    case G.Failure{+actual,operation,source,target,error}:selected(~S,U32.is_eq(Graph.key(~S,actual),Graph.key(~S,relation)),G.Failure{actual,operation,source,target,error},rest)
25	def select_notice(~S:Data,~E:Data,relation:G.Descriptor<S>,notice:A.Notice<S,E>,rest:List<&2,G.Failure<S>>) -> List<&2,G.Failure<S>>:
26	  match notice:
27	    case A.RelationFailed{failure}:select_failure(~S,relation,failure,rest)
28	    case _:rest
29	# Extract relation failures matching the descriptor key, preserving notice order.
30	# Other notice variants are omitted; no payload owners or reader positions change.
31	def failures(~S:Data,~E:Data,+relation:G.Descriptor<S>,notices:List<&2,A.Notice<S,E>>) -> List<&2,G.Failure<S>>:
32	  match notices:
33	    case []:[]
34	    case notice <> rest:select_notice(~S,~E,relation,notice,failures(~S,~E,relation,rest))
35	# Project visible and retained failures separately from a detached snapshot.
36	# Preserve its tick and retention boundary; this does not acknowledge a reader.
37	def view(~S:Data,~E:Data,+relation:G.Descriptor<S>,snapshot:Ev.Snapshot<A.Notice<S,E>>) -> FailureView<S,E>:
38	  match snapshot:
39	    case Ev.Snapshot{visible,retained,_,tick,boundary}:FailureView{relation,failures(~S,~E,relation,visible),failures(~S,~E,relation,retained),tick,boundary}
40	def joined(~S:Data,~C:Type,~R:Type,~E:Data,relation:G.Descriptor<S>,cursor:Maybe<&2,Tick.Tick>,observed:Ev.Runtime<S,C,R,A.Notice<S,E>> & Ev.Snapshot<A.Notice<S,E>>) -> F.Frame<S,C,R,E> & FailureView<S,E>:
41	  (runtime,snapshot)=observed
42	  (F.Frame{runtime,cursor},view(~S,~E,relation,snapshot))
43	# Return the runtime frame with a detached failure view. Preserve the Inspector
44	# cursor and runtime reader positions; inspection does not drain retained notices.
45	def read(~S:Data,~C:Type,~R:Type,~E:Data,relation:G.Descriptor<S>,frame:F.Frame<S,C,R,E>) -> F.Frame<S,C,R,E> & FailureView<S,E>:
46	  match frame:
47	    case F.Frame{runtime,cursor}:joined(~S,~C,~R,~E,relation,cursor,Ev.inspect(~S,~C,~R,~A.Notice<S,E>,runtime))
48	# Recover the descriptor carried by this declaration, without validation.
49	def descriptor(~S:Data,declaration:Declaration<S>) -> G.Descriptor<S>:
50	  match declaration:
51	    case Declaration{relation}:relation
52	# Build the read capability for this declaration. It exposes only selected
53	# failures and timing metadata, returning the affine frame after inspection.
54	def inspect(~S:Data,~C:Type,~R:Type,~E:Data,~declaration:Declaration<S>) -> Cap.ValueRead<F.Frame<S,C,R,E>,FailureView<S,E>>:
55	  Cap.ValueRead{frame => read(~S,~C,~R,~E,descriptor(~S,declaration),frame)}